30,695 research outputs found
A route generator concept for aircraft onboard fault monitoring
Because of the increasingly complex environments in which the flight crews of commercial aviation aircraft must operate, a research effort is currently underway at NASA Langley Research Center to investigate the potential benefits of intelligent cockpit aids, and to establish guidelines for the application of artificial intelligence techniques to advanced flight management concepts. The segment of this research area that concentrates on automated fault monitoring and diagnosis requires that a reference frame exist, against which the current state of the aircraft may be compared to determine the existence of a fault. This paper describes a computer program which generates the position of that reference frame that specifies the horizontal flight route
Orbital thermal analysis of lattice structured spacecraft using color video display techniques
A color video display technique is demonstrated as a tool for rapid determination of thermal problems during the preliminary design of complex space systems. A thermal analysis is presented for the lattice-structured Earth Observation Satellite (EOS) spacecraft at 32 points in a baseline non Sun-synchronous (60 deg inclination) orbit. Large temperature variations (on the order of 150 K) were observed on the majority of the members. A gradual decrease in temperature was observed as the spacecraft traversed the Earth's shadow, followed by a sudden rise in temperature (100 K) as the spacecraft exited the shadow. Heating rate and temperature histories of selected members and color graphic displays of temperatures on the spacecraft are presented
Searching for the most powerful thermonuclear X-ray bursts with the Neil Gehrels Swift Observatory
We searched for thermonuclear X-ray bursts from Galactic neutron stars in all
event mode data of the Neil Gehrels Swift Observatory collected until March 31,
2018. In particular, we are interested in the intermediate-duration bursts
(shell flashes fueled by thick helium piles) with the ill-understood phenomenon
of strong flux fluctuations. Nine such bursts have been discussed in the
literature to date. Swift is particularly suitable for finding additional
examples. We find and list a total of 134 X-ray bursts; 44 are detected with
BAT only, 41 with XRT only, and 49 with both. Twenty-eight bursts involve
automatic slews. We find 12 intermediate-duration bursts, all detected in
observations involving automatic slews. Five show remarkably long
Eddington-limited phases in excess of 200 s. Five show fluctuations during the
decay phase; four of which are first discussed in the present study. We discuss
the general properties of the fluctuations, considering also 7 literature
cases. In general two types of fluctuations are observed: fast ones, with a
typical timescale of 1 s and up and downward fluctuations of up to 70%, and
slow ones, with a typical timescale of 1 min and only downward fluctuations of
up to 90%. The latter look like partial eclipses because the burst decay
remains visible in the residual emission. We revisit the interpretation of this
phenomenon in the context of the new data set and find that it has not changed
fundamentally despite the expanded data set. It is thought to be due to a
disturbance of the accretion disk by outflowing matter and photons, causing
obscuration and reflection due to Thompson scattering in an orbiting highly
ionized cloud or structure above or below the disk. We discuss in detail the
most pronounced burster SAX J1712.6-3739. One of the bursts from this source is
unusual in that it lasts longer than 5600 s, but does not appear to be a
superburst.Comment: Accepted for publication in Astronomy & Astrophysics, 29 pages, 12
figures. Version 2 has 3 bursts from IGR J17480-2446 re-identified to 2 from
Swift J174805.3-244637 and 1 from EXO 1745-24
Blood product transfusion in emergency department patients: A case-control study of practice patterns and impact on outcome
Definitions of comorbid conditions. (DOCX 13 kb
Screening High-z GRBs with BAT Prompt Emission Properties
Detecting high-z GRBs is important for constraining the GRB formation rate,
and tracing the history of re-ionization and metallicity of the universe. Based
on the current sample of GRBs detected by Swift with known redshifts, we
investigated the relationship between red-shift, and spectral and temporal
characteristics, using the BAT event-by-event data. We found red-shift trends
for the peak-flux-normalized temporal width T90, the light curve variance, the
peak flux, and the photon index in simple power-law fit to the BAT event data.
We have constructed criteria for screening GRBs with high red-shifts. This will
enable us to provide a much faster alert to the GRB community of possible
high-z bursts.Comment: 4 pages, 4 figures, to be published in the proceedings of ''Gamma Ray
Bursts 2007'', Santa Fe, New Mexico, November 5-
Oceanic stochastic parametrizations in a seasonal forecast system
We study the impact of three stochastic parametrizations in the ocean
component of a coupled model, on forecast reliability over seasonal timescales.
The relative impacts of these schemes upon the ocean mean state and ensemble
spread are analyzed. The oceanic variability induced by the atmospheric forcing
of the coupled system is, in most regions, the major source of ensemble spread.
The largest impact on spread and bias came from the Stochastically Perturbed
Parametrization Tendency (SPPT) scheme - which has proven particularly
effective in the atmosphere. The key regions affected are eddy-active regions,
namely the western boundary currents and the Southern Ocean. However, unlike
its impact in the atmosphere, SPPT in the ocean did not result in a significant
decrease in forecast error. Whilst there are good grounds for implementing
stochastic schemes in ocean models, our results suggest that they will have to
be more sophisticated. Some suggestions for next-generation stochastic schemes
are made.Comment: 24 pages, 3 figure
Oceanic stochastic parametrizations in a seasonal forecast system
We study the impact of three stochastic parametrizations in the ocean
component of a coupled model, on forecast reliability over seasonal timescales.
The relative impacts of these schemes upon the ocean mean state and ensemble
spread are analyzed. The oceanic variability induced by the atmospheric forcing
of the coupled system is, in most regions, the major source of ensemble spread.
The largest impact on spread and bias came from the Stochastically Perturbed
Parametrization Tendency (SPPT) scheme - which has proven particularly
effective in the atmosphere. The key regions affected are eddy-active regions,
namely the western boundary currents and the Southern Ocean. However, unlike
its impact in the atmosphere, SPPT in the ocean did not result in a significant
decrease in forecast error. Whilst there are good grounds for implementing
stochastic schemes in ocean models, our results suggest that they will have to
be more sophisticated. Some suggestions for next-generation stochastic schemes
are made.Comment: 24 pages, 3 figure
Does the Supreme Court Follow the Economic Returns? A Response to A Macrotheory of the Court
Today, there is a widespread idea that parents need to learn how to carry out their roles as parents. Practices of parental learning operate throughout society. This article deals with one particular practice of parental learning, namely nanny TV, and the way in which ideal parents are constructed through such programmes. The point of departure is SOS family, a series broadcast on Swedish television in 2008. Proceeding from the theorising of governmentality developed in the wake of the work of Michel Foucault, we analyse the parental ideals conveyed in the series, as an example of the way parents are constituted as subjects in the ‘advanced liberal society’ of today. The ideal parent is a subject who, guided by the coach, is constantly endeavouring to achieve a makeover. The objective of this endeavour, however, is self-control, whereby the parents will in the end become their own coaches.
EEG Source Imaging Indices of Cognitive Control Show Associations with Dopamine System Genes.
Cognitive or executive control is a critical mental ability, an important marker of mental illness, and among the most heritable of neurocognitive traits. Two candidate genes, catechol-O-methyltransferase (COMT) and DRD4, which both have a roles in the regulation of cortical dopamine, have been consistently associated with cognitive control. Here, we predicted that individuals with the COMT Met/Met allele would show improved response execution and inhibition as indexed by event-related potentials in a Go/NoGo task, while individuals with the DRD4 7-repeat allele would show impaired brain activity. We used independent component analysis (ICA) to separate brain source processes contributing to high-density EEG scalp signals recorded during the task. As expected, individuals with the DRD4 7-repeat polymorphism had reduced parietal P3 source and scalp responses to response (Go) compared to those without the 7-repeat. Contrary to our expectation, the COMT homozygous Met allele was associated with a smaller frontal P3 source and scalp response to response-inhibition (NoGo) stimuli, suggesting that while more dopamine in frontal cortical areas has advantages in some tasks, it may also compromise response inhibition function. An interaction effect emerged for P3 source responses to Go stimuli. These were reduced in those with both the 7-repeat DRD4 allele and either the COMT Val/Val or the Met/Met homozygous polymorphisms but not in those with the heterozygous Val/Met polymorphism. This epistatic interaction between DRD4 and COMT replicates findings that too little or too much dopamine impairs cognitive control. The anatomic and functional separated maximally independent cortical EEG sources proved more informative than scalp channel measures for genetic studies of brain function and thus better elucidate the complex mechanisms in psychiatric illness
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